A Sect of Iranian Shi'a Islamic Muslim which existed during the crusades. Founded by Hassan Sabah at the fortress of Alamut in 1090 A.D. They were known for Assassinating leaders of the knights templar, often under the influence of the drug hashish. Brought into the light in recent times by the game Assassins Creed, where the player character is a Hashashin assassin.

Person One: "I love the hashashin!"
Person Two: "Why?"
Person One: "If not for them, we would not be smoking hash !"